S0-called touch screens enjoy increasing popularity as input device for electronic devices such as mobile telephones, minicomputers, entertainment electronic devices etc., since these make possible a comfortable and clear control of numerous functions without a large number of switches, controllers or other input means having to be expensively installed. Instead, images for example of such input means can be displayed on a touch screen and a user can perform an input by touching the displayed image of a switch with the finger, or running the finger over the image of a slide controller, thus imitating the movement with which he would operate a real slide controller.
Other input concepts manage entirely without representing input means. There are concepts, for example, which are based on the idea that the touch screen where forming a type of window through which a detail of a larger image located underneath is visible, which can represent a user surface, a map or the like, and by running the finger over the surface of the touch screen the visible detail of the image can be shifted.
Also known are input devices, e.g. for electronic cash systems, which scan and reproduce the signature performed by a customer with a special input pin on a touch screen.
The versatility of touch screens gives rise to a desire for utilising them also for controlling electronic devices installed in motor vehicles. However, this creates the problem that in a travelling motor vehicle, changing accelerations continually act on the touch screen and its user, be it because of road irregularities, which jolt the vehicle or centrifugal forces that occur when negotiating curves. This can make it difficult for a user to perform a movement on a touch screen exactly as intended. However, when deviations from the intended movement sequence caused through external influences lead to a control error, this is merely irksome to the user in the most benign of cases, since the input has to be cancelled and repeated; under unfavourable conditions an unexpected reaction of a device to a faulty input can irritate the driver of the vehicle, thus impairing the safety of the vehicle.
In order to remedy this problem, an input device was proposed in US 2011/0082620 A1, with which the size of a sensitive region of the touch screen, which has to be touched for triggering a desired action, of a so-called “soft button”, is variable as a function of the intensity of the accelerations to which the touch screen is subjected and can, in particular, become larger than the images of keys displayed on the touch screen, which indicate to the user the position of the soft buttons. This conventional solution, however, is only applicable on a touch screen whose soft buttons react to being touched. For operating concepts, which are based on sensing movements of the finger on the surface of the touch screen, this approach is not suitable.
In addition, other objects, desirable features and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background.